Hypoxia activates the hypoxia-inducible factor-1α/vascular endothelial growth factor pathway in a prostatic stromal cell line: A mechanism for the pathogenesis of benign prostatic hyperplasia

Abstract

The development of benign prostatic hyperplasia (BPH) is closely related to hypoxia in the prostatic stroma, and the hypoxia-inducible factor-1α/vascular endothelial growth factor (HIF-1α/VEGF) pathway has been shown to significantly activate in response to hypoxia. The underlying mechanism for activation of this pathway in the pathogenesis of BPH remains unclear. We constructed HIF-1α overexpression and knockdown BPH stromal (WPMY-1) and epithelial (BPH-1) cell lines, which were cultured under different oxygen conditions (hypoxia, normoxia, and hypoxia + HIF-1α inhibitor). Quantitative real-time polymerase chain reaction (qPCR) and Western blotting were applied to detect the expression of the HIF-1α/VEGF pathway. Cell proliferation and apoptosis were analyzed by Cell Counting Kit-8 and flow cytometry. We used the miRWalk 2.0 database and Western blotting to predict the potential miRNA that selectively targets the HIF-1α/VEGF pathway, and verified the prediction by qPCR and dual-luciferase assays. In a BPH stromal cell line (WPMY-1), the expression of VEGF was in accordance with HIF-1α levels, elevated in the overexpression cells and decreased in the knockdown cells. Hypoxia-induced HIF-1α overexpression, which could be reversed by a HIF-1α inhibitor. Moreover, the HIF-1α inhibitor significantly depressed cellular proliferation and promoted apoptosis in hypoxic conditions, assessed by Cell Counting Kit-8 and flow cytometry. However, in the BPH epithelial cell line (BPH-1), the expression level of HIF-1α did not influence the expression of VEGF. Finally, a potential miRNA, miR-17-5p, regulating the HIF-1α/VEGF pathway was predicted from the miRWalk 2.0 database and Western blotting, and verified by qPCR and dual-luciferase assay. In hypoxia, activation of the HIF-1α/VEGF pathway plays a crucial role in regulating cell proliferation in a BPH stromal cell line. Regulation by miR-17-5p may be the potential mechanism for the activation of this pathway. Regulation of this pathway may be involved in the pathogenesis of BPH.